/* A simple server in the internet domain using TCP
   The port number is passed as an argument */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>

void error(const char *msg)
{
    	perror(msg);
    	exit(1);
}

int main(int argc, char *argv[])
{
     	int sockfd, newsockfd, portno;
     	socklen_t clilen;
     	char buffer[256];
     	struct sockaddr_in serv_addr, cli_addr;
     	int n;
     	if (argc < 2) {
         	fprintf(stderr,"ERROR, no port provided\n");
         	exit(1);
     	}
     	sockfd = socket(AF_INET, SOCK_STREAM, 0);
     	if (sockfd < 0) 
        	error("ERROR opening socket");
     	bzero((char *) &serv_addr, sizeof(serv_addr));
     	portno = atoi(argv[1]);
     	serv_addr.sin_family = AF_INET;
     	serv_addr.sin_addr.s_addr = INADDR_ANY;
     	serv_addr.sin_port = htons(portno);
     	if (bind(sockfd, (struct sockaddr *) &serv_addr,
              	sizeof(serv_addr)) < 0) 
              	error("ERROR on binding");
     	listen(sockfd,5);
     	clilen = sizeof(cli_addr);
     

	while(1){

		newsockfd = accept(sockfd, 
                 	(struct sockaddr *) &cli_addr, 
                 	&clilen);
     		if (newsockfd < 0) 
          		error("ERROR on accept");
     		bzero(buffer,256);
     		n = read(newsockfd,buffer,255);
     		if (n < 0) error("ERROR reading from socket");
     		printf("Here is the message: %s\n",buffer);
     		n = write(newsockfd,"I got your message",18);
     		if (n < 0) error("ERROR writing to socket");
		}
     	close(newsockfd);
     	close(sockfd);
     	return 0; 
}
